1. Field of the Invention
The present invention relates to a process for cleaning parts of spinneret assemblies that had become fouled during use in a synthetic organic filament production process and had to be removed from service. More particularly, the invention concerns such a process in which hydraulic jets are used to clean the fouled spinneret assembly parts for re-use in the filament production process.
2. Description of the Prior Art
In commercial processes for the manufacture of fibers from synthetic organic polymers by dry spinning, wet spinning, melt spinning, or the like, the fibers are formed by extrusion of polymer solutions or melted polymer through orifices of spinneret assemblies. In such extrusion operations, the orifices, as well as other parts of the spinneret assemblies, eventually become fouled with polymeric residues and/or inorganic particles. Such fouled assemblies cause difficulties in spinning continuity and product quality and therefore, must be removed from service.
Over the last several decades, various methods have been developed for cleaning fouled spinneret assemblies for re-use. Fiber Producer, v. 5, no. 1, "Spinnerets: Selecting Steels and Cleaning Methods", (February 1977) and Fiber Producer, v. 8, no. 1, L. A. Langley and V. Jelms, "A Study of Spinnerette Cleaning Practices" (February 1980) review the known methods. The methods include the use of anhydrous molten salt baths, acid baths (e.g., usually containing nitric acid) combustion, pyrolysis, fluidized bed furnaces, ultrasonics and the like, as well as various combinations of these methods. Although each of the methods has been used successfully, each has certain disadvantages. For example, baths of molten salts or acids are corrosive. Combustion, pyrolysis and high temperature fluidized-beds require careful temperature control. High temperatures can cause excessive local oxidation or distortion of a part. A process for cleaning fouled spinnerets of a commercial plant that produces dry-spun spandex currently employs a series of acid baths, rinses, and ultrasonic cleaning devices.
An object of the present invention is to provide an efficient, inexpensive and non-damaging alternative method for cleaning fouled parts of spinneret assemblies.